All-trans-retinoic acids (ATRA) is one of the biologically active metabolites of vitamin A which plays an important role in cell differentiation and proliferation (MB. Reeves et al. 2007, Science). The molecular basis of its action has not been fully elucidated. It was previously shown (F. Papa et al. 2007, Int.J.Immun.Pharm.) that ATRA treatment of normal human keratinocytes resulted in growth suppression, increase of complex I content and reduction of the NADH-UQ oxidoreductase enzymatic activity. These effects were associated with enhanced level of GRIM-19. We found that induction of cAMP-PKA signalling, by dibutyryl cyclic AMP or okadaic acid, restores the complex I activity inhibited by ATRA, indicating an interplay between ATRA and PKA signal transduction on regulation of cellular bioenergetics. Mitochondrial proteome has to be considered as a non-static entity, that shows characteristic changes according to the functional state of the cell. To monitor the effect of ATRA on mitochondria keratinocytes protein profile a widesearch proteomic approach was used. In ATRA treated cells, a large number of mitochondrial proteins, were found to be up or down expressed with respect to control cells. In particular ATRA cell-treatment appeared to affect proteins which are synthesized in very low amount, as the case of regulatory proteins. Two proteins spots, down regulated in mitochondria of ATRA treated keratinocytes, were identified by mass spectrometry analysis as ATP synthase beta subunit, component of complex V, and protein disulfide-isomerase A6. These results indicate an effect of ATRA on the expression of mitochondrial OXPHOS complexes.

Work is presented on the role of cAMP-dependent protein phosphorylation in post-translational processing and biosynthesis of complex I subunits in mammalian cell cultures. PKA-mediated phosphorylation of the NDUFS4 subunit of complex I promotes in cell cultures in vivo import/maturation in mitochondria of the precursor of this protein. The import promotion appears to be associated with the observed cAMP-dependent stimulation of the catalytic activity of complex I. These effects of PICA are counteracted by activation of protein phosphatase(s). PKA and the transcription factor CREB play a critical role in the biosynthesis of complex I subunits. CREB phosphorylation, by PKA and/or CaMKs, activates at nuclear and mitochondrial level a transcriptional regulatory cascade which promotes the concerted expression of nuclear and mitochondrial encoded subunits of complex I and other respiratory chain proteins. (C) 2010 Elsevier B.V. All rights reserved.

Normal healing of fractures is a complex process that relies heavily on a cascade of consecutive activations of immune cells and mediators. This mechanism somewhat overlaps with all processes related to bone metabolism, from the absence of unions to heterotopic ossifications and osteoporosis. We aimed to review and describe this intricate process of bone metabolism with particular focus on abnormal function and to exemplify it with a series of clinical cases which could justify their practical importance. The elbow has great potential for fracture healing but it is very sensitive to prolonged immobilization which can easily lead to intra-articular adherences and stiffness. In addition, the interosseus membrane facilitates communication between the regenerative environments when both radius and ulna are fractured. Such extensive injuries, around the proximal forearm, can lead to heterotopic ossifications and synostosis, which decrease sagittal range of motion through impingement and even block rotational movement through bone bridges. Increased knowledge and awareness of the biological mechanism of fracture healing, will have great improvement in the pharmacological adjuvant treatment of elbow injuries.

Periodontics has evolved from a simplistic model to a more complex interplay between infection and host response. Genetic factors have been a new addition to the list of risk factors for periodontal diseases. The processes leading to destruction and regeneration of the destroyed tissues are of great interest to both researchers and clinicians. The selective susceptibility of subjects for periodontitis has remained an enigma and wide varieties of risk factors have been implicated for the manifestation and progression of periodontitis. Emerging pathway models suggest that gene-environment interactions are etiologically important in disease pathogenesis. The current practical utility of genetic knowledge in periodontitis is limited. Allelic variants at multiple gene loci probably influence periodontitis susceptibility. The pro-inflammatory cytokine interleukin-1 (IL-1) is a key modulator of host responses to microbial infection and a major modulator of extracellular matrix catabolism and bone resorption, and polymorphisms in the IL-1 gene cluster have been associated with an increased risk of developing severe adult periodontitis. The aim of this study was to test if polymorphisms of genes of IL-1α+4845 and IL-1β +3954 were linked with periodontitis, in a case-control study population, delimited to a specific geographic area, in association with microbiological findings. The polymorphisms observed in IL-1α+4845 and IL-1β+3954 single nucleotide polymorphisms (SNPs), was significantly different among the study groups (healthy controls, mild, moderate and severe periodontitis with p<0.05, d.f.=1. We found a significant correlation between the severe form of periodontitis and the presence of composite genotype (p < 0.05, d.f.=1, calculated among healthy vs. severe). Furthermore a statistically significant association between the presence of bacteria and periodontitis was detected (p<0.05, d.f.=1). In the current investigation findings were concordant with literature observations.

Applications of laser therapy in biostimulation and healing injured tissues are widely described in medical literature. The present study focuses on the effects of laser irradiation on the growth rate and differentiation of human osteoblast-like cells seeded on titanium or zirconia surfaces. Cells were laser irradiated with low therapeutical doses at different intervals and the effects of irradiation were evaluated at each time-point. After 3 hours lasered cells showed an enhanced mitogen activity compared to non-lasered control cells and a higher alkaline phosphatase activity, marker of bone formation. At the same time, the mRNA of RUNX2 and OSTERIX, two genes involved in osteoblast differentiation, showed a clear decrease in lasered cells. This reached the lowest value 6 to 12 hours after irradiation, after which the transcripts started to increase, indicating that the laser treatment did promote the osteogenic potential of growth-induced cells. These results indicate that Low Level Laser Treatment (LLLT) stimulates osteogenic cell proliferation

Aims: Sepsis is the leading cause of death in intensive care units usually related to the number and the severity of organ failure, but the mechanisms remain to be fully established. Findings of microvascular flow abnormalities, decreased oxygen consumption and elevated tissue oxygen tensions suggest that problems may lay in cellular oxygen utilization rather than in oxygen delivery per se. Several serum factors, released during sepsis syndrome, might be involved in induction of cytopathic hypoxia and increase of cellular oxidative stress. Main methods: Human fibroblast cultures were incubated 12 hours with 10% v/v severe septic patients sera and measurements were carried out on cellular oxygen consumption, mitochondrial respiratory enzymes activity, H2O2 generation and serum levels of cytokines/chemokines by multiplex assay. Key findings: In fibroblast cultures a significant depression of cellular respiration and activity of mitochondrial complexes and increased H2O2 production was observed and, IL-1after incubation with septic sera showing increased levels of TNF IL-6. Significance: During sepsis syndrome some increased cytokines might target specific mitochondrial enzymes inducing an impairment of cellular energy metabolism leading to multiple organ failure

Increased ROS (cellular reactive oxygen species) are characteristic of both fibrosis and tumour development. ROS induce the trans-differentiation to myofibroblasts, the activated form of fibroblasts able to promote cancer progression. Here, we report the role of ROS produced in response to dysfunctions of mitochondrial complex I, in fibroblast activation and in tumour progression. We studied human fibroblasts with mitochondrial dysfunctions of complex I, leading to hyperproduction of ROS. We demonstrated that ROS level produced by the mutated fibroblasts correlates with their activation. The increase of ROS in these cells provides a greater ability to remodel the extracellular matrix leading to an increased motility and invasiveness. Furthermore, we evidentiated that in hypoxic conditions these fibroblasts cause HIF-1 alpha stabilization and promote a proinvasive phenotype of human melanoma cells through secretion of cytokines. These data suggest a possible role of deregulated mitochondrial ROS production in fibrosis evolution as well as in cancer progression and invasion.

Introduction: Today, we frequently find patients taking oral anticoagulant therapy (OAT), a prophylaxis against the occurrence of thromboembolic events. An oral surgeon needs to know how to better manage such patients, in order to avoid hemorrhagic and thromboembolic complications. Materials and methods: A group of 193 patients (119 men aged between 46 and 82 and 74 women aged between 54 and 76) undergoing OAT for more than 5 years were managed with a standardized management protocol and a 2-months follow-up. The aim of the present study was to apply a protocol, which could provide a safe intra- and postoperative management of patients on OAT. Results: Among the 193 patients, only 2 had postoperative complications. Conclusions: We think that the protocol used in the present study can be used for complete safety in the treatment of this type of patients. Keywords: Oral Anticoagulant Therapy (OAT), Tranexamic Acid, Oral Surgery

The NDUFS4 subunit of complex I of the mammalian respiratory chain has a fully conserved carboxy-terminus with a canonical RVSTK phosphorylation site. Immunochemical analysis with specific antibodies shows that the serine in this site of the protein is natively present in complex I in both the phosphorylated and non-phosphorylated state. Two-dimensional IEF/SDS-PAGE electrophoresis, (32)P labelling and immunodetection show that "in vitro" PKA phosphorylates the serine in the C-terminus of the NDUFS4 subunit in isolated bovine complex I. (32)P labelling and TLC phosphoaminoacid mapping show that PKA phosphorylates serine and threonine residues in the purified heterologous human NDUFS4 protein.

Introduction. Maxillary bone losses often require additional regenerative procedures: as a supplement to the procedures of tissue regeneration, a platelet concentrate called PRF (Platelet Rich Fibrin) was tested for the first time in France by Dr. Choukroun. Aim of the present study is to investigate, clinically and histologically, the potential use of PRF, associated with deproteinized bovine bone (Bio-Oss), as grafting materials in pre-implantology sinus grafting of severe maxillary atrophy, in comparison with a control group, in which only deproteinized bovine bone (Bio-Oss) was used as reconstructive material. Materials and Methods. 60 patients were recruited using the cluster-sampling method; inclusion criteria were maxillary atrophy with residual ridge < 5mm. The major atrophies in selected patients involved sinus-lift, with a second-look reopening for the implant insertion phase. The used grafting materials were: a) Bio-Oss and b) amorphous and membranous PRF together with Bio-Oss. We performed all operations by means of piezosurgery in order to reduce trauma and to optimize the design of the operculum on the cortical bone. The reopening of the surgical area was scheduled at 3 different times. Results. 72 sinus lifts were performed with subsequent implants insertions. We want to underline how the histological results proved that the samples collected after 106 days (Early protocol) with the adding of PRF were constituted by lamellar bone tissue with an interposed stroma that appeared relaxed and richly vascularized. Conclusions. The use of PRF and piezosurgery reduced the healing time, compared to the 150 days described in literature, favoring optimal bone regeneration. At 106 days, it is already possible to achieve good primary stability of endosseous implants, though lacking of functional loading. Keywords: Reconstructive Surgery, Platelet Rich Fibrin, Grafting Materials, Bone replacement.

The results of the present work show that the exposure of pregnant rats to low doses of all-trans-retinoic acid (ATRA) (2.5 mg/kg body weight) results in postnatal dysfunction of complex I of the respiratory chain in the cerebellum of the offspring. ATRA had no effect on the postnatal expression of complex I and did not exert any direct inhibitory effect on the enzymatic activity of the complex. The ATRA embryonic exposure resulted, however, in a marked increase in the level of carbonylated proteins in the mitochondrial fraction of the cerebellum, in particular of complex I subunits. The postnatal increase of the carbonylated proteins correlated directly with the inhibition of the activity of complex I. ATRA had, on the other hand, no effect on oxygen free-radical scavengers. It is proposed that embryonic exposure to ATRA results in impairment of protein surveillance in the cerebellum, which persists after birth and results in accumulation of oxidatively damaged complex I.

A study is presented on the expression of mitochondrial oxidative phosphorylation complexes in exponentially growing and serum-starved, quiescent human fibroblast cultures. The functional levels of respiratory complexes I and III and complex V (adenosine triphosphate (ATP) synthase) were found to be severely depressed in serum-starved fibroblasts. The depression of oxidative phosphorylation system (OXPHOS) complexes was associated with reduced levels of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and the down-stream nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factors (TFAM). In serum-starved fibroblasts decrease of the catalytic activity of AMP cyclic dependent protein kinase (PKA) and phosphorylation of cAMP response element-binding protein (CREB), the transcription coactivator of the PGC-1α gene, was found. Hydroxytyrosol prevented the decline in the expression of the PGC-1α transcription cascade of OXPHOS complexes in serum-starved fibroblast cultures. The positive effect of HT was associated with activation of PKA and CREB phosphorylation. These results show involvement of PKA, CREB and PGC-1α in the regulation of OXPHOS in cell transition from the replicating to the quiescent state.

INTRODUCTION: Burning Mouth Syndrome (BMS) is characterized by burning sensation and pain in the mouth with or without inflammatory signs and specific lesions. MATERIALS AND METHODS: Aim of the present study was to investigate about a possible correlation between the Burning Mouth Syndrome and oxidative stress. We recruited 18 healthy female patients between 54 and 68 years of age with a diagnosis of Burning Mouth Syndrome. Oxidative stress assessment was performed by means of an integrated analytical system composed of a photometer and a mini-centrifuge (FRAS4, H and D s.r.l., Parma, Italy). Samples of whole capillary blood were taken by a finger puncture in a heparinized tube and immediately centrifuged; a small amount of samples plasma (10 microL) were thereafter tested for total oxidant capacity (d-ROMs test) and biological antioxidant potential as iron-reducing activity (BAP test) (Diacron International s.r.l., Grosseto, Italy). RESULTS: Our results indicate that female patients affected by Burning Mouth Syndrome show significantly different d-ROMs and BAP levels, similar to those present in oxidative stress condition with respect to the general population. It was also emphasized that, after the most painful phase, the levels representing the present oxidative stress, progressively return to normal, even if still significantly higher 7 days after, with respect to the normal population. No similar study was performed up to now. CONCLUSIONS: This study confirms the effectiveness of antioxidant treatments in the patients affected by BMS, in order to prevent or decrease the onset of oxidative stress and the consequent increased risk of oxidative-related systemic diseases.

In mammals, complex I (NADH-ubiquinone oxidoreductase) of the mitochondrial respiratory chain has 31 supernumerary subunits in addition to the 14 conserved from prokaryotes to humans. Multiplicity of structural protein components, as well as of biogenesis factors, makes complex I a sensible pace-maker of mitochondrial respiration. The work reviewed here shows that the cAMP/PKA pathway regulates the biogenesis, assembly and catalytic activity of complex I and mitochondrial oxygen superoxide production. The structural, functional and regulatory complexity of complex I, renders it particularly vulnerable to genetic and sporadic pathological factors. Complex I dysfunction has, indeed, been found, to be associated with several human diseases. Knowledge of the pathogenetic mechanisms of these diseases can help to develop new therapeutic strategies. (C) 2011 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.

This authoritative reference presents the modern concepts of mesenchymal stem cells (MSCs) and biomaterials as they pertain to the dental field. The book is organized around three main topics: MSCs biology, advanced biomaterials, and clinical applications. The chapters present basic information on stem cell biology and physiology, modern biomaterials that improve bone tissue regeneration, the biomatrices like platelet-rich fibrin (PRF) used to functionalize the biomaterials surface, the strategic and safe intraoral seats of harvesting, the new sources for MSCs, as well as the future perspectives and new challenges in these exciting fields. The contributors are top scientists with a great deal of experience in regenerative dentistry and biomedical research. They offer an international perspective and are richly cross-disciplinary, representing academia, research, and industry. MSCs and Innovative Biomaterials in Dentistry is indispensable reading for students, researchers, and clinicians who need to stay up-to-date on the cutting-edge developments of tissue engineering and regenerative medicine applied to dental sciences.

Objectives: The aim of the present study is to assess the implant osteo-integration, as well as the course of bone regeneration and healing processes, thanks to the sinus lift procedure and by using PRF (R) as a filling material, in association with the Bio-Oss (R). Materials and Methods: 23 patients, requiring maxillary sinus lift in order to place implants into posterior maxillary region, were involved in this study. Selected cases, in which the height of the residual bone was superior to 5 mm, were adopted for surgical procedure of &quot;one-stage sinus lift&quot; (implant insertion concurrently occured with sinus lift resulting 6-9 months the healing and integration time). Before inserting the implant, a small quantity of filling material was placed in the cavity. For this purpose the bone fragment, stored in saline solution, was employed mixed with Bio-Oss (R) and PRF (R), after being ground. Results: All patients reported no pain to percussion, no sign of tissue suffering in the soft peri-implant tissues, the presence of an optimal primary stability of the inserted implants and a significant increase in the peri-implant bone density. Conclusions: In all cases included in this protocol, the Authors observed a successful implant-prosthetic rehabilitation, according with Albrektsson criteria.